In a vehicle having driven tracks on the opposite sides thereof it is highly desirable to selectively provide power to one or both tracks, or to provide no power to either track, dependent on operating conditions. These features in combination with a braking system for each track, will provide a tracked-vehicle with high efficiency of operation. Not only is appropriate straight-line performance provided, but also highly efficient selective turning of the vehicle is obtained. Such steering is achieved through the selective relative releasing and holding of the individual clutch or brake discs located on the opposite sides of the vehicle.
Such relative holding is generally achieved through the movement of nonrotary friction material into engagement with a rotary member to thereby retard movement of that member. Additionally, nonrotary friction material may be appropriately positioned on the opposite side of that member to serve as a reaction. In this way the rotary member is contacted on both sides by portions of the friction material. Over a period of time, the friction material experiences considerable wear upon repeated engagement and disengagement of the brake system and must be replaced. Yet in the prior systems, the replacement of such friction material is not readily allowed for. For example, it is time consuming and difficult to remove the usual annular ring of friction material from the power train because almost complete disassembly thereof is required. The serviceability requirements are further complicated when it is desired to incorporate a single brake assembly for independently braking a pair of axially spaced members without having to remove the members during servicing of the brake assembly.
Moreover, it should be understood that each of the brake assemblies should be highly efficient, compact, and of relatively simple construction so as to be capable of convenient servicing.
The present invention is directed toward overcoming one or more of the problems as set forth above.